In GB No. 2,158,867A, there is disclosed a lock having means for reading a key, for verifying data read from the key and releasing a key-receiving cylinder of the lock for rotation upon verification of the data. A cam is secured on the cylinder and the disc may be used for driving a bolt or other member which is to be controlled by the lock. A lever is pivoted in a housing of the lock and is spring-loaded to a position in which the lever obstructs turning of the cam and therefore of the lock cylinder. For pivoting the lever to a releasing position, there is provided a solenoid having an armature which is arranged to act on the lever and pivot the lever against the action of its spring. When the data read from the key has been verified, the solenoid is energised, thereby releasing the cylinder for turning by means of the key.
The arrangement described in GB No. 2,158,867A is satisfactory, in a case where electrical energy for energisation of the solenoid is derived from a mains supply. However, the prior arrangement is less satisfactory in cases where the lock is to be energised from a battery of cells. If the battery is small, the life of the battery will be relatively short. In order to achieve a long battery life, it would be necessary to provide a battery with a large capacity.